net.sf.saxon.functions

## Class StringJoin

- java.lang.Object
- - net.sf.saxon.expr.Expression
  - - net.sf.saxon.expr.FunctionCall
    - - net.sf.saxon.functions.SystemFunctionCall
      - - net.sf.saxon.functions.StringJoin

- All Implemented Interfaces:
    Serializable, SourceLocator, LocationProvider, SaxonLocator, Callable, InstructionInfo, Locator

      public class StringJoin
      extends SystemFunctionCall
      implements Callable

  xf:string-join(string* $sequence, string $separator)
  See Also:
    Serialized Form

- - ### Field Summary

    - ### Fields inherited from class net.sf.saxon.functions.SystemFunctionCall

      `operation`

    - ### Fields inherited from class net.sf.saxon.expr.FunctionCall

      `argument`

    - ### Fields inherited from class net.sf.saxon.expr.Expression

      `EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, INHERITED_CONTEXT, INSPECTION_CONTEXT, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, NAVIGATION_CONTEXT, NODE_VALUE_CONTEXT, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, W3C_CONSUMING, W3C_FREE_RANGING, W3C_GROUP_CONSUMING, W3C_MOTIONLESS, WATCH_METHOD`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `StringJoin()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `Sequence` | `call(XPathContext context, Sequence[] arguments)` Evaluate the expression
    `int` | `computeCardinality()` Determine the cardinality of the function.
    `Expression` | `copy()` Copy an expression.
    `boolean` | `equals(Object o)` Determine whether two expressions are equivalent
    `StringValue` | `evaluateItem(XPathContext c)` Evaluate an expression as a single item.
    `ExpressionCompiler` | `getExpressionCompiler()` Return the compiler of the StringJoin expression
    `int` | `getImplementationMethod()` An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
    `StreamingAdjunct` | `getStreamingAdjunct()` Get a class that supports streamed evaluation of this expression
    `boolean` | `isReturnEmptyIfEmpty()`
    `Expression` | `optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType)` Perform optimisation of an expression and its subexpressions.
    `void` | `process(XPathContext context)` Process the instruction in push mode.
    `void` | `setReturnEmptyIfEmpty(boolean option)` Indicate that when the input sequence (first argument) is empty, the function should return an empty sequence rather than an empty string

    - ### Methods inherited from class net.sf.saxon.functions.SystemFunctionCall

      `addContextDocumentArgument, addDocToPathMap, bindStaticContext, checkArguments, computeSpecialProperties, equalOrNull, getContextNode, getConvertingCallable, getDefaultArgumentNode, getDetails, getErrorCodeForTypeErrors, getFunctionItemType, getItemType, getOperation, getRequiredType, iterateSubExpressionInfo, makeSystemFunction, setDetails, useContextItemAsDefault`

    - ### Methods inherited from class net.sf.saxon.expr.FunctionCall

      `addExternalFunctionCallToPathMap, checkArgumentCount, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck`

    - ### Methods inherited from class net.sf.saxon.expr.Expression

      `addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getStreamability, getSystemId, getSystemId, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, iterateEvents, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toPattern, toStreamingPattern, typeError`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### StringJoin

          public StringJoin()

  - ### Method Detail

    - #### setReturnEmptyIfEmpty

          public void setReturnEmptyIfEmpty(boolean option)

      Indicate that when the input sequence (first argument) is empty, the function should return an empty sequence rather than an empty string
      Parameters:
        `option` - true if an empty sequence should be returned when the input is an empty sequence.

    - #### isReturnEmptyIfEmpty

          public boolean isReturnEmptyIfEmpty()

    - #### computeCardinality

          public int computeCardinality()

      Determine the cardinality of the function.
      Overrides:
        `computeCardinality` in class `SystemFunctionCall`
      Returns:
        the computed cardinality, as one of the values `StaticProperty.ALLOWS_ZERO_OR_ONE`, `StaticProperty.EXACTLY_ONE`, `StaticProperty.ALLOWS_ONE_OR_MORE`, `StaticProperty.ALLOWS_ZERO_OR_MORE`

    - #### copy

          public Expression copy()

      Description copied from class: `SystemFunctionCall`
      Copy an expression. This makes a deep copy.
      Overrides:
        `copy` in class `SystemFunctionCall`
      Returns:
        the copy of the original expression

    - #### equals

          public boolean equals(Object o)

      Determine whether two expressions are equivalent
      Overrides:
        `equals` in class `SystemFunctionCall`

    - #### getImplementationMethod

          public int getImplementationMethod()

      Description copied from class: `SystemFunctionCall`
      An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided directly. The other methods will always be available indirectly, using an implementation that relies on one of the other methods.
      Overrides:
        `getImplementationMethod` in class `SystemFunctionCall`
      Returns:
        the implementation method, for example `Expression.ITERATE_METHOD` or `Expression.EVALUATE_METHOD` or `Expression.PROCESS_METHOD`

    - #### optimize

          public Expression optimize(ExpressionVisitor visitor,
                            ExpressionVisitor.ContextItemType contextItemType)
                              throws XPathException

      Description copied from class: `SystemFunctionCall`
      Perform optimisation of an expression and its subexpressions.

      This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

      Overrides:
        `optimize` in class `SystemFunctionCall`
      Parameters:
        `visitor` - an expression visitor
        `contextItemType` - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to `Type.ITEM_TYPE`
      Returns:
        the original expression, rewritten if appropriate to optimize execution
      Throws:
        `XPathException` - if an error is discovered during this phase (typically a type error)

    - #### evaluateItem

          public StringValue evaluateItem(XPathContext c)
                                   throws XPathException

      Description copied from class: `Expression`
      Evaluate an expression as a single item. This always returns either a single Item or null (denoting the empty sequence). No conversion is done. This method should not be used unless the static type of the expression is a subtype of "item" or "item?": that is, it should not be called if the expression may return a sequence. There is no guarantee that this condition will be detected.
      Overrides:
        `evaluateItem` in class `Expression`
      Parameters:
        `c` - The context in which the expression is to be evaluated
      Returns:
        the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence
      Throws:
        `XPathException` - if any dynamic error occurs evaluating the expression

    - #### process

          public void process(XPathContext context)
                       throws XPathException

      Process the instruction in push mode. This avoids constructing the concatenated string in memory, instead its parts can be sent straight to the serializer.
      Overrides:
        `process` in class `Expression`
      Parameters:
        `context` - The dynamic context, giving access to the current node, the current variables, etc.
      Throws:
        `XPathException` - if a dynamic error occurs

    - #### call

          public Sequence call(XPathContext context,
                      Sequence[] arguments)
                        throws XPathException

      Evaluate the expression
      Specified by:
        `call` in interface `Callable`
      Parameters:
        `context` - the dynamic evaluation context
        `arguments` - the values of the arguments, supplied as Sequences
      Returns:
        the result of the evaluation, in the form of a Sequence
      Throws:
        `XPathException` - if a dynamic error occurs during the evaluation of the expression

    - #### getExpressionCompiler

          public ExpressionCompiler getExpressionCompiler()

      Return the compiler of the StringJoin expression
      Overrides:
        `getExpressionCompiler` in class `Expression`
      Returns:
        the relevant ExpressionCompiler

    - #### getStreamingAdjunct

          public StreamingAdjunct getStreamingAdjunct()

      Get a class that supports streamed evaluation of this expression
      Overrides:
        `getStreamingAdjunct` in class `Expression`
      Returns:
        the relevant StreamingAdjunct, or null if none is available

Copyright (c) 2004-2013 Saxonica Limited. All rights reserved.